One of the most memorable moments from Sunday's Oscars ceremony was Lady Gaga's powerful tribute to survivors of sexual assault, which the singer identifies herself as -- though not all of her family members knew it until Sunday.

Gaga took to Instagram on Tuesday to describe how her grandmother and aunt called her after the ceremony, when Gaga performed her nominated song "Til It Happens To You" while joined onstage by 50 fellow sexual assault survivors, to express their shock and offer their support.

"I never told them I was a survivor," she wrote next to a picture of her grandmother and aunt. "I was too ashamed. Too afraid. And it took me a long time to even admit it to myself because I'm Catholic and I knew it was evil but I thought it was my fault. I thought it was my fault for ten years."

"The morning after the Oscars," Gaga continues, "when I talked to my grandmother Ronnie, with tears in her eyes I could hear them welling through the phone she said to me, 'My darling granddaughter, I've never been more proud of you than I am today.' Something I have kept a secret for so long that I was more ashamed of than anything - became the thing the women in my life were the most proud of. And not just any women, the ones I look up to the most. #BeBrave #speakup#tilithappenstoyou"